Multi-segment continuum robots provide for snake-like movement and positioning by deformation of internal structures of the robotic mechanisms as opposed to the relative deformation of individual rigid links. As such, continuum robots can be used to extend deeper into cavities to perform functions including, for example, search and rescue in disaster relief, nuclear handling, and minimally invasive surgical procedures. However, adoption of continuum robots has been limited due to a lack of controls methods to prevent damage to the robotic structure and the environment when the device is inserted into a cavity of unknown dimensions. During insertion into a complex environment, such as a surgical or disaster site, continuum robots must interact safely while being subject to a multitude of unknown contact sites along the robot arm length.
Passive compliance techniques have been proposed to achieve safe interaction without the need for additional sensing and complex control. Passively compliant structures contain flexible members which comply with environment interaction forces without explicit compliant control. Though these systems have shown promise in providing a measure of safety, they suffer from a number of significant disadvantages for exploration and intervention in unstructured environments. By the very nature of their design, passive compliant systems are limited in their accuracy and the magnitude of forces that can be applied during environment interaction. Conversely, the measure of safety provided by passive compliance is limited by the flexibility of the system. Additionally, the compliance adds uncertainty and modeling difficulties that degrade trajectory tracking performance. Thus, a need exists for active compliant instrumentation that can safely interact with the surrounding environment while maintaining manipulation precision and delivering adequate forces for executing manipulation tasks.